Substrate processing apparatus and substrate processing method

ABSTRACT

An outer covering wall ( 26 ) and an inner covering wall ( 27 ), which are capable of surrounding a rotor ( 24 ), can be horizontally moved. A wafer carrier waiting portion ( 30 ) is disposed right below the rotor ( 24 ). A wafer holding member ( 41 ) included in a wafer lifter ( 40 ) moves into a wafer carrier (C) containing wafers (W) and mounted on a stage ( 31 ) (sliding table  32 ) included in the wafer carrier waiting portion ( 30 ), lifts up the wafers (W) and transfers the wafers (W) to the rotor ( 24 ). The outer covering wall ( 26 ) or the inner covering wall ( 27 ) surrounds the rotor ( 24 ) to define a processing chamber. The wafers (W) held on the rotor ( 24 ) are subjected to a cleaning process in the processing chamber.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a substrate processing apparatusfor processing substrates, such as semiconductor wafers, by apredetermined process and a substrate processing method.

[0003] 2. Description of the Related Art

[0004] A semiconductor device fabricating process employs a wafercleaning apparatus that cleans semiconductor wafers, i.e., substrates,with a cleaning liquid, such as pure water or a desired chemical liquid,to clean the wafers of contaminants including organic contaminants andmetallic impurities, and a wafer drying apparatus that removes liquiddrops from wafers for drying by means of an inert gas, such as N₂ gas,or a highly volatile and hydrophilic IPA vapor. Each of those knownwafer cleaning apparatus and wafer drying apparatus is of a batchprocessing type that processes a plurality of semiconductor waferssimultaneously in a wafer cleaning chamber or a wafer drying chamber.

[0005] Batch-type wafer cleaning apparatus are disclosed in, forexample, U.S. Pat. Nos. 5,784,797, 5,678,320 and 5,232,328. Thebatch-type wafer cleaning apparatus has a wafer carrying device thatcarries semiconductor wafers into a wafer cleaning chamber formedtherein. Generally, the wafer carrying device has a wafer chuckincluding a pair of gripping members. The wafer chuck grips a pluralityof semiconductor wafers collectively. A lateral rotor is supported forrotation in the wafer cleaning chamber. The plurality of semiconductorwafers carried into the wafer cleaning chamber by the wafer carryingdevice are held by holding members mounted on the rotor in the wafercleaning chamber. More concretely, in the wafer cleaning apparatusdisclosed in U.S. Pat. Nos. 5,784,797 and 5,678,320, the wafer chuck ofa wafer carrying device is moved through a doorway formed in a frontwall of a wafer cleaning chamber (a wall facing the wafer carryingdevice moving toward a wafer cleaning chamber) into the wafer cleaningchamber from a side in front of a wafer cleaning tank (from a side infront of the rotor), and wafers are transferred from the wafer chuck tothe rotor.

[0006] A known wafer cleaning apparatus 400 shown in FIG. 32 has a wafercleaning tank 402 defining a wafer cleaning chamber 401. A rotor 405capable of holding semiconductor wafers W and of rotating can be movedthrough an opening 403 formed in the front end of the cleaning tank 402into and out of the cleaning tank 402. With the rotor 405 disposedoutside the wafer cleaning tank 402, the semiconductor wafers W aretransferred between the rotor 405 and a chuck having gripping members409 a and 409 b and attached to a carrying device. The rotor 405 ismoved into and out of the cleaning tank 402 and is rotated by a drivingmechanism 407. A shaft 480 is connected to the rotor 405.

[0007] A batch-type wafer drying apparatus is disclosed in, for example,JP-A No. Hei 6-112186. This prior art batch-type wafer drying apparatushas a wafer cleaning tank defining a wafer drying chamber and having anupper wall provided with a doorway. A lateral rotor is disposed in thewafer cleaning chamber. A wafer holding hand capable of verticalmovement for handling semiconductor wafers is detachably mounted on therotor. The wafer holding hand is raised through the doorway to aposition above the wafer cleaning tank to transfer semiconductor wafersbetween the wafer holding hand and a wafer carrying device. When dryingsemiconductor wafers by this batch-type wafer drying apparatus, thesemiconductor wafers are transferred from the wafer carrying device tothe wafer holding hand and the wafer holding hand is lowered to placethe wafers in the wafer drying chamber. Subsequently, the wafer holdinghand holding the semiconductor wafers is mounted on the rotor to loadthe rotor with the wafers, and the wafers are dried. After the wafershave been dried, the wafer holding hand is separated from the rotor, israised to a position above the wafer drying tank, and the dried wafersare griped by the wafer carrying device.

[0008] The wafer cleaning apparatus disclosed in U.S. Pat. Nos.5,784,797 and 5,678,320 need to secure a space sufficient for the waferchuck to operate in the wafer cleaning chamber and hence the size of thewafer cleaning chamber must be increased accordingly. Since the waferchuck operates in a limited space in the wafer chamber, the operation ofthe wafer chuck must be carefully controlled so that the wafer chuck maynot collide against the wall of the wafer cleaning tank. Consequently,the wafer carrying device must execute complicated operations and acontrol program for controlling the wafer carrying device is inevitablycomplicated.

[0009] Although the wafer chuck of the wafer cleaning apparatus 400shown in FIG. 39 does not need to operate in a limited space, the waferchuck must be controlled so that the gripping members 409 a and 409 b ofthe wafer chuck may not collide against the holding members 406 of therotor 405. Consequently, a complicated control program is necessary forcontrolling the wafer chuck and the rotor 405.

[0010] In the wafer drying apparatus disclosed in JP-A No. Hei 6-112186,the wafer holding hand is always in contact with the semiconductorwafers throughout a period in which the wafers are carried into thedrying chamber, dried and carried out of the drying chamber. Therefore,there is the possibility that particles and the like adhering to andremaining on the wafer holding hand adhere again to the wafers tocontaminate the dried wafers.

SUMMARY OF THE INVENTION

[0011] Accordingly, it is an object of the present invention to providea substrate processing apparatus having a small substrate processingchamber and facilitating work for carrying substrates into and out ofthe substrate processing chamber, and a substrate processing method.Another object of the present invention is to provide a substrateprocessing apparatus and a substrate processing method capable ofpreventing the contamination of substrates.

[0012] To achieve the objects, the present invention provides asubstrate processing apparatus including: a substrate processing portionat which a plurality of substrates are treated by a process; a substratewaiting portion at which the substrates stand by for the process, thewaiting portion being arranged below the processing portion; and asubstrate lifter including a substrate supporting member configured tosupport the substrates from below the substrates, the supporting memberbeing capable of vertical movement, wherein the lifter supports thesubstrates placed at the waiting portion and raises the substratesthereby moves the substrates from the waiting portion to the processingportion, and wherein the lifter supports the substrates placed in theprocessing portion and lowers the substrates thereby moves thesubstrates from the processing portion to the waiting portion.

[0013] The present invention also provides a substrate processingapparatus including: a substrate processing portion at which a pluralityof substrates are-treated by a process; a substrate waiting portion atwhich the substrates stand by for the process, the waiting portion beingarranged above the processing portion; and a substrate lifter includinga substrate supporting member configured to support the substrates frombelow the substrates, the supporting member being capable of verticalmovement, wherein the lifter supports the substrates placed at thewaiting portion and lowers the substrates thereby moves the substratesfrom the waiting portion to the processing portion, and wherein thelifter supports the substrates placed in the processing portion andraises the substrates thereby moves the substrates from the processingportion to the waiting portion, and wherein the lifter is disposedoutside of the processing portion.

[0014] According to another respect of the present invention, asubstrate processing method is provided, the method including the stepsof: carrying a substrate container containing a plurality of substratesinto a container waiting portion disposed below a substrate processingportion for processing substrates; supporting the substrates containedin the substrate container, and raising the substrate to the processingportion disposed above the waiting portion; treating the substrates by aprocess at the substrate processing portion; supporting the substrateswhich have been treated and lowering the substrates into a substratecontainer; and carrying out the substrate container containing theprocessed substrates, which have been treated, from the waiting portion.

[0015] The present invention also provides a substrate processing methodincluding the steps of: holding a plurality of substrates by an arm andcarrying a substrates into a substrate waiting portion disposed above asubstrate processing portion; delivering the substrates from the arm toa supporting member; lowering the supporting member thereby moving thesubstrates to the processing portion; holding the substrates by asubstrate holding device provided at the processing portion; furtherlowering the supporting member thereby withdrawing the supporting memberfrom the processing portion; and treating the substrates by a process atthe substrate processing portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a perspective view of a wafer cleaning apparatus in afirst embodiment according to the present invention;

[0017]FIG. 2 is a schematic plan view of the wafer cleaning apparatusshown in FIG. 1;

[0018]FIG. 3 is a sectional view of a cleaning unit included in thewafer cleaning apparatus shown in FIG. 2;

[0019]FIG. 4 is a sectional view of a cleaning device included in thecleaning unit, in which an inner covering member is placed outside anouter covering member;

[0020]FIG. 5 is a sectional view of the cleaning device of the cleaningunit, in which the inner covering member is placed inside the outercovering member;

[0021]FIG. 6 is a sectional view taken on line A-A in FIG. 5;

[0022]FIG. 7 is a perspective view of a rotor included in the cleaningdevice;

[0023]FIG. 8 is a perspective view of arms, balance weights andprojections shown in FIG. 7;

[0024]FIG. 9 is an enlarged perspective view of a vertical wall andcondition selecting members shown in FIG. 7;

[0025]FIG. 10 is a perspective view of the condition selecting membersand the projections in a state where a holding mechanism is in areleasing state;

[0026]FIG. 11 is a perspective view of the condition selecting membersand the projections in a state where the holding mechanism is in aholding state;

[0027]FIG. 11A is a perspective view of another mechanism alternative tothat shown in FIGS. 9 to 11;

[0028]FIG. 12 is a plan view and a front elevation of a wafer containercarrier for carrying a wafer container between a stage included in aloading/unloading unit, and a wafer container waiting portion includedin the cleaning unit;

[0029]FIG. 13 is a side elevation of a wafer lifter included in thecleaning unit;

[0030]FIG. 14 is a block diagram of assistance in explaining anoperation to be executed when a pressure exceeding a predetermined levelis applied to wafers during the raising operation of the wafer lifter;

[0031] FIGS. 15 to 18 are typical views of assistance in explainingoperations of the wafer lifter for moving wafers to the rotor;

[0032]FIG. 19 is a sectional view of an outer covering member providedwith a drip preventing device;

[0033]FIG. 20 is a perspective view of the drip preventing device shownin FIG. 19;

[0034]FIG. 21 is a perspective view of a wafer cleaning apparatus in asecond embodiment according to the present invention;

[0035]FIG. 22 is a schematic plan view of the wafer cleaning apparatusshown in FIG. 21;

[0036]FIG. 23 is a perspective view of essential portions of areceiving/delivering unit and a loading/unloading unit shown in FIG. 22;

[0037]FIG. 24 is a sectional view of a cleaning unit included in thewafer cleaning apparatus shown in FIG. 21;

[0038]FIG. 25 is a schematic front elevation of an essential portion ofthe cleaning unit shown in FIG. 24;

[0039]FIG. 26 is a typical view of a first supporting member of a waferlifter shown in FIG. 25 supporting a wafer;

[0040]FIG. 27 is a typical view of a second supporting member of thewafer lifter shown in FIG. 25 supporting a wafer;

[0041] FIGS. 28 to 35 are typical views of assistance in explaining atransfer procedure for transferring wafers between a wafer carrying armand a rotor;

[0042]FIG. 36 is a schematic sectional view of a wafer cleaningapparatus in a modification of the second embodiment;

[0043]FIG. 37 is a perspective view of a wafer lifter in a modification;

[0044]FIG. 38 is a perspective view of a wafer carrying arm in amodification; and

[0045]FIG. 39 is a perspective view of a conventional wafer cleaningapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] A wafer cleaning apparatus in a first embodiment according to thepresent invention will be described with reference to FIGS. 1 to 20. Thewafer cleaning apparatus carries out all the operations for carrying,cleaning, drying and delivering semiconductor wafers in a batchprocessing apparatus.

[0047] Referring to FIGS. 1 and 2, the wafer cleaning apparatus 1 has acontainer receiving/delivering unit 2, i.e., so-called “in/out port”,for receiving and delivering a wafer carrier C or a container containingwafers W, a cleaning unit 3 for cleaning wafers W, a loading/unloadingunit 4 interposed between the in/out port 2 and the cleaning unit 3 tocarry a wafer carrier C into and out of the cleaning unit 3, a wafercarrier cleaning unit 5 for cleaning wafer carriers C, and a wafercarrier storage unit 6 for storing a plurality of wafer carriers C. Thewafer cleaning apparatus 1 has also a power unit 7 and a chemical liquidtank box 8.

[0048] The in/out port 2 is provided with a stage 10 capable ofsupporting four wafer carriers C thereon. A carrying path 11 is formedin the in/out port 2 on the stage 10 along a line on which wafercarriers C are arranged. A wafer carrier carrying mechanism 12 movesalong the carrying path 11 to carry a wafer carrier C placed on thestage 10 to the loading/unloading unit 4 and to carry a wafer carrier Cfrom the loading/unloading unit 4 onto the stage 10. A wafer carrier Cis capable of containing, for example, twenty-six wafers in a verticalposition in a horizontal arrangement.

[0049] The loading/unloading unit 4 has a stage 13 for supporting awafer carrier C thereon. A wafer carrier C transferred from the in/outport 2 onto the stage 13 is carried by the wafer carrier carryingmechanism 12, which will be described in detail later, into the cleaningunit 3. The wafer carrier carrying mechanism 12 carries the wafercarrier C from the cleaning unit 3 onto the stage 13. Since a wafercarrier C is carried from the stage 10 to the stage 13 by turning an armincluded in the wafer carrier carrying mechanism 12, the wafer carrier Cplaced on the stage 13 faces a direction opposite a direction in whichthe wafer carrier C faces on the stage 10. Therefore, the direction inwhich the wafer carrier C faces on the stage 13 is reversed by-areversing mechanism, not shown.

[0050] The cleaning unit 3 and the loading/unloading unit 4 areseparated by a partition wall 14 provided with an opening 14 a throughwhich a wafer carrier C is moved between the cleaning unit 3 and theloading/unloading unit 4. The opening 14 a can be closed by a shutter15. The shutter 15 is closed while the cleaning unit 3 is in operation.The shutter 15 is opened when carrying a wafer carrier C from theloading/unloading unit 4 into the cleaning unit 3 and when carrying awafer carrier C from the cleaning unit 3 to the loading/unloading unit4.

[0051] The wafer carrier cleaning unit 5 has a wafer carrier cleaningtank 16 to clean an empty wafer carrier C which has been emptied byunloading wafers W therefrom in the cleaning unit 3.

[0052] In the wafer carrier storage unit 6, empty wafer carriers Cemptied by unloading wafers W to be cleaned therefrom are storedtemporarily and empty wafer carriers C are stored therein to receivecleaned wafers W. A plurality of wafer carriers C can be stored instacks. The wafer carrier storage unit 6 is provided with a wafercarrier moving mechanism for transporting a desired one of the pluralityof wafer carriers C stored in the wafer carrier storage unit 6 to thestage 10 and for placing wafer carriers C at desired positions in thewafer carrier storage unit 6 for storage.

[0053] The cleaning unit 3 will be described with reference to FIGS. 3to 6.

[0054] Referring to FIG. 3, the cleaning unit 3 is provided therein witha substrate cleaning portion (i.e., a substrate processing portion) anda substrate carrier waiting portion 30 (i.e., a substrate waitingportion). A cleaning device 20 is provided at the cleaning portion. Thewaiting portion 30 is disposed right under the cleaning device 20 tokeep a wafer carrier C temporarily. Furthermore, a wafer lifter 40 (i.e.so-called “wafer hand”) is provided in the cleaning unit 3. The waferlifter 40 raises wafers W standing by for processing in a wafer carrierC at the waiting portion 30 to move the wafers W to the cleaning device20. The wafer lifter 40 also returns the wafers W from the cleaningdevice 20 to the wafer carrier C kept at the waiting portion 30. Thecleaning device 20 removes a resist mask and an etch residue, such asfragments of a polymer layer, remaining on wafers W processed by anetching process. The cleaning device 20 includes a vertical support wall18, a motor 23 having a drive shaft 23 a and fixedly held on the supportwall 18 in a horizontal position, a rotor 24 connected to the driveshaft 23 a of the motor 23, a cylindrical support tube 25 surroundingthe drive shaft 23 a of the motor 23, a cylindrical outer covering wall26 supported on the support tube 25, and a cylindrical inner coveringwall 27.

[0055] The outer covering wall 26 can be horizontally moved between aworking position indicated by two-dot chain lines in FIG. 3 around therotor 24 and a back position indicated by continuous lines in FIG. 3around the support tube 25. The inner covering wall 27 has a diametersmaller than that of the outer covering wall 26. The inner covering wall27 can be horizontally moved between a working position around the rotor24 as shown in FIG. 5 and a back position around the support tube 25 asshown in FIGS. 3 and 4. When wafers W are carried into and carried outof the rotor 24, the outer covering wall 26 and the inner covering wall27 are held at their back positions as shown in FIG. 3. When the outercovering wall 26 is at the working position and the inner covering wall27 is at the back position as shown in FIG. 4, a first chamber 51 (FIG.4) is defined by the outer covering wall 26, a vertical wall 26 a nearerto the motor 23 and a vertical wall 26 b farther from the motor 23. Whenthe inner covering wall 27 is at the working position as shown in FIG.5, a second chamber 52 is defined by the inner covering wall 27 and thevertical walls 26 a and 26 b. The first chamber 51 and the secondchamber 52 are sealed by sealing mechanisms in closed spaces.

[0056] The vertical wall 26 a is attached to the support tube 25. Thedrive shaft 23 a is supported in bearings 28 on the support tube 25. Alabyrinth seal 29 is formed between the vertical wall 26 a and an endpart of the support tube 25 to prevent particles produced by the motor23 from entering the chambers 51 and 52. A support member 25 a ismounted on an end part of the support tube 25 on the side of the motor23 to support the outer covering wall 26 and the inner covering wall 27.As shown in FIGS. 4 to 6, two spray pipes 54 provided with a pluralityof jetting holes 53 are attached in a horizontal position to an upperpart of the vertical wall 26 b opposite the vertical wall 26 a withrespect to the rotor 24. Pure water, IPA, N₂ gas or a chemical liquidsupplied from a source, not shown, can be sprayed by the spray pipes 54.When the outer covering wall 26 is at the working position and the innercovering wall 27 is at the back position as shown in FIG. 4, the spraypipes 54 are in an upper position of the first chamber 51 as shown inFIG. 6.

[0057] Two spray pipes 56 provided with a plurality of jetting holes 55are attached in a horizontal position to the inner covering wall 27.Pure water, IPA or a chemical liquid supplied from a source, not shown,can be sprayed by the spray pipes 56. As shown in FIG. 6, a N₂ gasjetting pipe 57 similar in construction to the spray pipes 56 isdisposed near the spray pipe 56. When the outer covering wall 26 and theinner covering wall 27 are at their working positions as shown in FIG.5, the spray pipes 54 extend in a space between the outer covering wall26 and the inner covering wall 27, i.e., outside the second chamber 52,and the spray pipes 56 extend in an upper position of the second chamber52.

[0058] A first drain port 61 is formed in a lower part of the verticalwall 26 b to drain used pure water, a used chemical liquid or used IPAfrom the first chamber 51 in a state shown in FIG. 4. A second drainport 62 is formed in the vertical wall 26 b at a position above thefirst drain port 61 to drain used pure water, a used chemical liquid orused IPA from the second chamber 52 in a state shown in FIG. 5. A firstdrain line 63 and a second drain line 64 are connected to the firstdrain port 61 and the second drain port 62, respectively.

[0059] A first discharge 65 is formed in an upper part of the verticalwall 26 b to discharge a gas from the first chamber 51 in a state shownin FIG. 4. A second discharge port 66 is formed in the vertical wall 26b at a position below the first discharge port 65 to discharge a gasfrom the second chamber 52 in a state shown in FIG. 5. A first dischargeline 67 and a second discharge line 68 are connected to the firstdischarge port 65 and the second discharge port 66, respectively.

[0060] The rotor 24 is capable of holding, for example, twenty-sixwafers W in a horizontal arrangement. As shown in FIG. 7, the rotor 24has a pair of disks 70 a and 70 b, first holding members 71 a and 71 bextended between the pair of disks 70 a and 70 b so as to be symmetricalwith respect to a vertical plane including the axis of the rotor 24,second holding members 72 a and 72 b extended between the pair of disks70 a and 70 b so as to be symmetrical with respect to a vertical planeincluding the axis of the rotor 24, and a pair of holding mechanisms 73a and 73 b for fixedly holding wafers W on the rotor 24.

[0061] The first holding members 71 a and 71 b and the second holdingmembers 72 a and 72 b are provided with a plurality of grooves 75 forreceiving peripheral parts of wafers W therein, respectively. At leastone of the holding members 71 a, 72 b, 72 a and 72 b is provided with apressure sensor.

[0062] As shown in FIGS. 7 and 8, the holding mechanism 73 a includes anarm 80 a disposed on the inner side of the disk 70 a, a balance weight81 a dispose on the outer side of the disk 70 a, an arm 84 a disposed onthe inner side of the disk 70 b, a balance weight 85 a disposed on theouter side of the disk 70 b, and a third holding member 83 a extendedbetween the arms 80 a and 84 a. The arm 80 a and the balance weight 81 aare fixedly connected to the opposite ends, respectively, of a shaft 89penetrating the disk 70 a for simultaneous turning. The arm 84 a and thebalance weight 85 a are fixedly connected to the opposite ends,respectively, of a shaft 89 penetrating the disk 70 b for simultaneousturning. The holding mechanism 73 b is similar in construction to theholding mechanism 73 a. The holding mechanism 73 b includes an arm 80 bdisposed on the inner side of the disk 70 a, a balance weight 81 bdispose on the outer side of the disk 70 a, an arm 84 b disposed on theinner side of the disk 70 b, a balance weight 85 b disposed on the outerside of the disk 70 b, and a third holding member 83 b extended betweenthe arms 80 b and 84 b. The arm 80 b and the balance weight 81 b arefixedly connected to the opposite ends, respectively, of a shaft 89penetrating the disk 70 a for simultaneous turning. The arm 84 b and thebalance weight 85 b are fixedly connected to the opposite ends,respectively, of a shaft 89 penetrating the disk 70 b for simultaneousturning. The third holding members 83 a and 83 b of the holdingmechanisms 73 a and 73 b are provided with a plurality of grooves 86 forreceiving peripheral portions of wafers W therein.

[0063] Stopping pins 87 project from the outer surfaces of the disks 70a and 70 b. When the third holding members 83 a and 83 b of the holdingmechanisms 73 a and 73 b are turned toward wafer holding positions,respectively, the outward turning of the balance weights 81 a, 81 b, 85a and 85 b is limited by the stopping pins 87 to prevent the balanceweights 81 a, 81 b, 85 a and 85 b from turning excessively outward andfrom touching the covering wall. As shown in FIG. 8, the balance weight85 a and 85 b supported on the disk 70 b adjacent to the vertical wall26 a are provided with curved projections 88 a and 88 b, respectively.

[0064] As shown in FIG. 9, an annular guide groove 90 is formed in theinner surface of the vertical wall 26 a on the side of the motor 23.Circular openings 91 a and 91 b are formed in the vertical wall 26 a atpositions on the guide groove 90 and respectively corresponding to theholding mechanisms 73 a and 73 b, and cylindrical condition selectingmembers 92 a and 92 b are fitted in the circular openings 91 a and 91 bso as to be turnable in the directions of the arrows θ. Curved slots 93a and 93 b having the shape of an arc of a circle corresponding to theannular guide groove 90 are formed in the front surfaces of thecondition selecting members 92 a and 92 b, respectively. The conditionselecting members 92 a and 92 b can be set in either an angular positionin which the curved slots 93 a and 93 b form portions of the guidegroove 90 as shown in FIG. 11 or an angular position in which the curvedslots 93 a and 93 b extend across the guide groove 90 as shown in FIG.10. The curved projections 88 a and 88 b of the balance weights 85 a and85 b can be fitted in the curved slots 93 a and 93 b, respectively. Thestate of the holding mechanisms 73 a and 73 b can be selectivelydetermined by the angular positions of the condition selecting members92 a and 92 b.

[0065] When the condition selecting members 92 a and 92 b are set sothat the curved slots 93 a and 93 b extend across the guide groove 90 asshown in FIG. 10 to set the balance weights 85 a and 85 b in a verticalposition, the holding mechanisms 73 a and 73 b are set in a waferreleasing state indicated by continuous lines in FIG. 7.

[0066] When the condition selecting members 92 a and 92 b are set sothat the curved slots 93 a and 93 b are continuous with the guide groove90 as shown in FIG. 11, the balance weights 85 a and 85 b divergeupward, the holding mechanisms 73 a and 73 b are set in a wafer holdingstate indicated by two-dot chain lines in FIG. 7. In this state, thecurved projections 88 a and 88 b of the balance weights 85 a and 85 bare able to move along the guide groove 90 and the curved slots 93 a and93 b continuous with the guide groove 90, so that the rotor 24 isallowed to rotate. Since the condition of the holding mechanism 73 a and73 b remains unchanged regardless of the angular position of the rotor24, the wafers W are not released. Therefore, it is possible to preventobstructing the supply of a cleaning liquid or a drying gas by wafers Wprojecting from the rotor 24 and to prevent damaging wafers W projectingfrom the rotor 24.

[0067] When the holding mechanisms 73 a and 73 b are in the waferholding state, wafers W are held firmly by the first holding members 71a and 71 b, the second holding members 72 a and 72 b and the thirdholding members 83 a and 83 b. As shown in FIG. 6, a triangle T1 formedby connecting points on the first holding member 71 a, the secondholding member 72 b and the third holding member 83 a at which eachwafer W is held is an acute triangle, and a triangle T2 formed byconnecting points on the first holding member 71 b, the second holdingmember 72 a and the third holding member 83 b at which each wafer W isheld is an acute triangle. Therefore, wafers W can be securely held onthe rotor 24 during the rotation of the rotor 24.

[0068]FIG. 6 shows notched wafers W held on the rotor 24. When holdingwafers W each provided with an orientation flat Wa indicated by a chainline as shown in FIG. 6 on the rotor 24, it is preferable to extend asupport rod S indicated by a chain line in FIG. 6 between the disks 70 aand 70 b of the rotor 24. The support rod S in contact with theorientation flats Wa of the wafers W held on the rotor 24 prevents theunnecessary turning of the wafers W on the rotor 24 during the rotationof the rotor 24.

[0069] As shown in FIG. 11A, the vertical wall 26 a may be provided onits inner surface with a circular guide rail 330 instead of the guidegroove 90. The circular guide rail 330 is provided with two gaps, andtwo turnable rails 331 a and 331 b having the shape of an arc of acircle corresponding to the circular guide rail 330 are placed in thegaps instead of the condition selecting members 92 a and 92 b. The stateof the holding mechanisms 73 a and 73 b can be selectively determined byselectively determining the angular positions of the rails 331 a and 331b. When the rails 331 a and 331 b are set so as to be continuous withthe guide rail 330, the holding mechanisms 73 a and 73 b are set in awafer holding state and the rotor 24 is allowed to rotate.

[0070] Referring again to FIG. 3, the wafer carrier waiting portion 30is provided with a stage 31. As shown in FIGS. 12(a) and 12(b), a wafercontainer carrier 35 or a carrier carrying mechanism, for carrying awafer carrier C between the waiting portion 30 and the loading/unloadingunit 4, includes a base 34 supported on the stages 13 and 31, two guiderails 33 laid on the base 34, and a sliding table 32 capable of movingalong the guide rails 33 between the stage 13 of the loading/unloadingunit 4 and the stage 31 of the waiting portion 30. The sliding table 32is moved by a cylinder actuator, not shown, to move a wafer carrier Cplaced on the sliding table 32 between the stages 13 and 31.

[0071] The sliding table 32 is provided with an opening in a portionthereof corresponding to the wafer containing part of a wafer carrier Cmounted thereon. The base 34 and the stage 31 are framed structures(skeletal structures). Therefore, a wafer supporting member 41 of thewafer lifter 40 is able to take out wafers W from and to put wafers W ina carrier C, which will be described later.

[0072] Referring to FIGS. 3 and 13, the wafer lifter 40 includes thewafer supporting member 41, a support bar 42 supporting the wafersupporting member 41, and a driving device 43 for vertically moving thesupport bar 42 to move raise and lower the wafer supporting member 41.

[0073] The driving device 43 includes a vertical threaded shaft 101, astepping motor 102 for rotating the threaded shaft 101, a guide rail 103extended in parallel to the threaded shaft 101, a sliding block 104provided with an internal thread mating with the external thread of thethreaded shaft 101, and slides 105 that slide along the guide rail 103.The stepping motor 102 drives the threaded shaft 101 for rotation tomove the wafer supporting member 41 vertically. The threaded shaft 101,the sliding block 104 and balls, not shown, form a ball screw.

[0074] The wafer supporting member 41 is provided with wafer holdinggrooves 41 a in its upper surface. The number of the wafer holdinggrooves 41 a is twice the number of wafers W contained in a wafercarrier C, for example, fifty-two. The pitch of the wafer holdinggrooves 41 a are equal to half that of the pitch of wafers W containedin a wafer carrier C. The wafer supporting member 41 can be horizontallyshifted on a base member 44 by a distance equal to the pitch of thewafer holding grooves 41 a, i.e., half the pitch of wafers contained ina wafer carrier C. More concretely, as shown in FIG. 13, a piston rodconnected to a piston included in a cylinder actuator 106 and connectedto the base member 44 is moved axially to shift the wafer supportingmember 41 horizontally by a distance equal to the pitch of the waferholding grooves 41 a. Thus, cleaned wafers W can be received in theholding grooves 41 a different from those in which the wafers W had beenreceived before the wafers W were cleaned, so that possibility that thecleaned wafers W are contaminated with particles and such adhering tothe grooves 41 a in which the wafers W had been received before the samewere cleaned can be reduced.

[0075] A piston rod connected to a piston included in a cylinderactuator 108 is connected to the base member 44 and the cylinderactuator 108 is attached to the support bar 42. A pressure regulator 113provided with a pressure-relief valve is connected to the cylinderactuator 108. When raising wafers W by the wafer supporting member 41 toload the rotor 24 with the wafers W, the pressure-relief valve of thepressure regulator 113 opens to relieve pressure working on the pistonof the cylinder actuator 108 upon the increase of pressure working onthe piston of the cylinder actuator 108 beyond a predetermined limit, sothat the piston rod of the cylinder actuator 108 is retracted.Therefore, breakage of the wafers W when loading the rotor 24 with thewafers W can be prevented even if a control apparatus for controllingthe wafer lifter 40 should malfunction. A sensor 111 detects thelowering of the piston rod. Upon the detection of the lowering of thepiston rod, the sensor 111 gives a detection signal to a controller 110,and then the controller 110 gives a command signal to an alarm device112 to make the alarm device 112 generate an alarm.

[0076] As shown in FIG. 3, a wafer detector 115 including a plurality ofpairs each of a light-emitting element and a light-receiving elementdisposed on the opposite sides, respectively, of a wafer carrying pathis disposed above the carrier waiting portion 30 to count the number ofwafers W as the wafers W pass by the wafer detector 115 and to findirregularly supported wafers (the so-called jump slots).

[0077] A series of operations of the wafer cleaning apparatus will bedescribed. Wafer carriers C each containing, for example, twenty-sixwafers W to be cleaned are carried onto the stage 10 of the in/out port2 by an operator or an automatic carrying device.

[0078] The wafer carrier carrying mechanism 12 carries one of the wafercarriers C placed on the stage 10 onto the sliding table 32 of thecontainer carrier 35 mounted on the stage 13 of the loading/unloadingunit 4. The wafer carrier C placed on the sliding stage 32 can be turnedthrough an angle of 180° in a horizontal plane by the reversingmechanism, not shown.

[0079] The shutter 15 is opened to open the opening 14 a of thepartition wall 14 and the sliding table 32 is moved onto the stage 31 ofthe carrier waiting portion 30 of the cleaning unit 3. The wafer carrierC is kept on the stage 31 of the carrier waiting portion 30.

[0080] Subsequently, the outer covering wall 26 and the inner coveringwall 27 of the cleaning device 20 are set at their back positions,respectively, as shown in FIG. 3.

[0081] Then, as shown in FIG. 15, the wafer lifter 40 is actuated toraise the wafers W contained in the wafer carrier C mounted on thesliding table 32 on the stage 31 of the carrier waiting portion 30 bythe wafer supporting member 41. While the wafers W is being raised, thewafer detector 115 counts the wafers W and examines the wafers W to seewhether there is any jump slot. Then, as shown in FIG. 16, the wafers Ware brought into contact with the first holding members 71 a and 71 band the second holding members 72 a and 72 b of the rotor 24 with theirperipheral portions received in the grooves 74 of the holding members 71a, 71 b, 72 a and 72 b. In this state, the condition selecting members92 a and 92 b are turned so as to enable the holding members 83 a and 83b of the holding mechanisms 73 a and 73 b to be brought into contactwith the wafers W from below the same to hold the wafers W on the rotor24 as shown in FIG. 17. Subsequently, the wafer supporting member 41 islowered.

[0082] Then, the outer covering wall 26 is moved to the working positionshown in FIG. 4 and a cleaning process is started. The empty wafercarrier C kept on the stage at the wafer carrier waiting portion 30 isreturned to the loading/unloading unit 4 by the container carrier 35 andis carried to the wafer carrier cleaning unit 5 by the wafer carriercarrying mechanism 12. The empty wafer carrier C is cleaned by thecarrier cleaning unit 5. A cleaned, empty wafer carrier C is carriedfrom the wafer carrier storage unit 6 to the carrier waiting portion 30by the wafer carrier carrying mechanism 12 and the container carrier 35.The cleaned, empty wafer carrier C is kept on the stage of the waitingportion 30.

[0083] In the cleaning process, the inner covering wall 27 is moved tothe working position shown in FIG. 5 and a first cleaning step isexecuted in the second chamber 52; the rotor 24 is rotated at apredetermined rotating speed and a chemical liquid (processing liquid)is sprayed by the spray pipes 56 on the wafers W to remove a resistremaining on the wafers W for cleaning.

[0084] After the first cleaning step has been completed, the innercovering wall 27 is retracted to the back position shown in FIG. 4, andthen a second cleaning step is executed in the first chamber 51; therotor 24 is rotated at a predetermined rotating speed and pure water issprayed by the spray pipes 54 on the wafers W for rinsing.

[0085] Subsequently, a spin drying step is executed in the first chamber51 in a state shown in FIG. 4, in which N₂ gas is jetted by the N₂ gasjetting pipe 57 while the rotor 24 is rotated at a rotating speed higherthan that at which the rotor 24 is rotated in the second cleaning step.

[0086] After the cleaning and drying steps have been completed and therotor 24 has been stopped, the outer covering wall 26 is retracted tothe back position (the inner covering wall 27 is held at the backposition) to expose the rotor 24. Then, the wafer supporting member 41of the wafer lifter 40 is raised, the cleaned wafers W are transferredfrom the rotor 24 to the wafer supporting member 41. The wafersupporting member 41 is shifted horizontally by a distance correspondingto the pitch of the wafer holding grooves 41 a before receiving thecleaned wafers W from the rotor 24 from a position at which the wafersupporting member 41 held the wafers W before the wafers W aretransferred to the rotor 24 for cleaning. Consequently, the cleanedwafers W are received in the wafer holding grooves 41 a different fromthose in which the wafers W subjected to the cleaning process had beenheld.

[0087] In the state where the cleaned wafers W are held on the wafersupporting member 41, the holding mechanisms 73 a and 73 b are in acondition shown in FIG. 17. Then, the condition selecting members 92 aand 92 b are turned to release the holding mechanisms 73 a and 73 b sothat the holding mechanisms 73 a and 73 b are set in a condition shownin FIG. 16. This releasing operation for releasing the holdingmechanisms 73 a and 73 b can be carried out only when the projections 88a and 88 b are in the curved slots 93 a and 93 b, respectively, and thereleasing operation cannot be performed when the projections 88 a and 88b are in the guide groove 90. Therefore, it is scarcely possible thatthe holding mechanisms 73 a and 73 b are released and the wafers W falloff the rotor 24 during the cleaning process.

[0088] The wafer supporting member 41 holding the cleaned wafers W islowered. The wafer detector 115 counts the cleaned wafers W forconfirmation while the cleaned wafers W are being moved downward. Thewafers W are received and held in the wafer holding grooves of the wafercarrier C when the wafer carrier C passes through the wafer carrier Ckept on the stage 31 of the carrier keeping device 30.

[0089] Then, the wafer carrier C containing the cleaned wafers W iscarried to the loading/unloading unit 4 by the container carrier 35 andto the stage 10 of the receiving/delivering unit by the wafer carriercarrying mechanism 12. The operator or the automatic carrying devicedelivers the wafer carrier C to the next destination.

[0090] Since the wafers W are supported from below the same on the wafersupporting member 41 while the wafers W are moved vertically, the wafersW do not need to be gripped by a gripping device when carrying thewafers W into the processing chamber and hence any special space for theoperation of a gripping device need not be secured in the processingchamber. Therefore, the processing chamber of the wafer cleaningapparatus is compact.

[0091] Since the wafers W can be loaded on and unloaded from the rotor24 only by the movement of the wafer supporting member 41 of the waferlifter 40, complicated control operations are unnecessary for loadingthe wafers W on and unloading the same from the rotor 24 of the cleaningdevice 20, the wafers W can be very easily loaded on and unloaded fromthe rotor 24, and the construction of the wafer cleaning apparatus canbe simplified.

[0092] Since the outer covering wall 26 and the inner covering wall 27can be moved between the working position and the back position and thespray pipes for spraying a chemical liquid and a rinsing liquid areplaced in the chambers defined by the covering walls 26 and 27,respectively, highly diversified cleaning processes can be carried out.

[0093] The outer covering wall 26 must be retracted before unloading thewafers W from the rotor 24 after the completion of the foregoingcleaning process. There is the possibility that the cleaning liquiddrips when the outer covering wall 26 is retracted. It is preferable toconnect a liquid collecting device 120 or a drip preventing device tothe front end of a lower part of the outer covering wall 26 as shown inFIG. 19 to collect the liquid dripped from the outer covering wall 26when the outer covering wall 26 is retracted. As shown in FIG. 20, theliquid collecting device 120 includes a liquid tray 121 connected to theouter covering wall 26 so as to be movable and a drain tray 122 providedwith a drain port 129. A liquid received by the liquid tray 121 isdrained into a drain line through the drain tray 122. Two supportmembers 123 a-and 123 b are fastened to the outer covering wall 26 withscrews. Opposite end parts of a pair of guide shafts 124 a and 124 b aresupported on the support members 123 a and 123 b. A slide member 125 isfixed to the liquid tray 121 and is supported for sliding on the guideshafts 124 a and 124 b. A compression coil spring 126 or the pressingelement is extended between the slide member 125 and the support member123 b. When the outer covering wall 26 is moved to the working position,the compression coil spring 126 is compressed and the front end wall 127of the liquid tray 121 is pressed against an end part 130 of thevertical wall 26 b by the resilience of the compression coil spring 126.In an initial stage of retraction of the outer covering wall 26 afterthe completion of the cleaning process, the front end wall 127 of theliquid tray 121 is kept in contact with the end part 130 of the verticalwall 26 b by the resilience of the compression coil spring 126.Therefore, the liquid that drips from the front end of the outercovering wall 26 upon the separation of the outer covering wall 26 fromthe vertical wall 26 b can be received by the liquid tray 121 to preventthe dripping of the liquid. The liquid received by the liquid tray 121flows along the bottom wall 128 of the liquid tray 121 and the draintray 122 and is drained through the drain port 129 into the drain line.Note that an air cylinder actuator may be used as the pressing elementinstead of the coil spring 126.

[0094] Modifications of the cleaning apparatus in the first embodimentare possible. For example, wafers taken out of a wafer carrier may becarried to carrier waiting portion 30, and then the wafers, standing byat waiting portion 30, may be raised to the rotor 24.

[0095] Although the cleaning apparatus in the first embodiment carriesout the cleaning process using a chemical liquid in the second chamber52 defined by the inner covering wall 27 and carries out the rinsing anddrying processes in the first chamber 51 defined by the first coveringwall 26, the cleaning process may be carried out in the first chamberdefined by the outer covering wall 26, the rinsing process may becarried out in the second chamber 52 defined by the inner covering wall27 or the first chamber 51 and the second chamber 52 may be alternatelyused for the cleaning process.

[0096] Although the cleaning apparatus in the first embodiments isprovided with the outer covering wall 26 and the inner covering wall 27to define the two processing chambers, the cleaning apparatus may beprovided with three or more covering walls or a single covering wall.

[0097] Although the cleaning apparatus in the first embodiment exposesthe rotor 24 by retracting the outer covering wall 26 and the innercovering wall 27 to their back positions, the vertical wall 26 b may beprovided with an opening covered and a cover covering the opening, andthe rotor 24 may be exposed by opening the cover and moving the rotor 24horizontally through the opening of the vertical wall 26 b.

[0098] A cleaning apparatus 201 in a second embodiment according to thepresent invention will be described hereinafter. Referring to FIGS. 21and 22, the cleaning apparatus 201 has a receiving/delivering unit,i.e., an in/our port 202 for receiving and delivering a wafer carrier Ccontaining wafers W, a loading/unloading unit 203 that takes out notcleaned wafers W from a wafer carrier C and puts cleaned wafers W into awafer carrier C, a wafer carrier storage unit 204 for storing wafercarriers C, and a cleaning unit 206 provided with a wafer cleaningdevice 205. The cleaning apparatus 201 is provided with a wafer carriercarrying table 207 that carries a wafer carrier C, and a wafer carryingdevice 208 that grips and carries wafers W. The wafer carrier carryingtable 207 can be moved between the in/out port 202 and theloading/unloading unit 203. The wafer carrying device 208 is able tomove between the loading/unloading unit 203 and the cleaning unit 206,more specifically, a transfer position 234 in the cleaning unit 206.

[0099] The in/out port 202 is provided with a stage 211 for supportingwafer carriers C thereon. The stage 211 is provided with a plurality ofopenings at stations 212, 213, 214 and 215 in which wafer carriers C areplaced. Lower peripheral parts of wafer carriers C are supported on theedges of the openings of the stations 212 to 215, respectively.Normally, wafer carriers C containing not cleaned wafers W are placed atthe stations 212 and 213 and wafer carriers C containing cleaned wafersWare placed at the stations 214 and 215. The loading/unloading unit 203has a stage 216 provided with a station 217.

[0100] The wafer carrier carrying table 207 can be moved by a tablemoving mechanism 218 in directions parallel to a direction in whichwafer carriers C are arranged on the stage 211, i.e., in directionsindicated by the arrows X in FIG. 22, and in directions parallel to adirection in which the in/out port 202, the loading/unloading unit 203and the cleaning unit 206 are arranged, i.e., in the directions of thearrows Y in FIG. 22. The wafer carrier carrying table 207 is movedthrough one of the openings of the stations 212 to 215 and 217 toreceive a wafer carrier C located at the corresponding station andcarries the wafer carrier C to another station.

[0101] Referring to FIG. 23, a loading/unloading hand 220 is disposedunder the stage 216 of the loading/unloading unit 203. Theloading/unloading hand 220 can be moved in vertical directions, i.e., inthe directions of the arrows Z, and can be turned in a horizontal planein the directions of the arrows θ by a lifting and turning mechanism,not shown. The loading/unloading hand 220 is provided in its uppersurface with a plurality of grooves 222 for receiving lower peripheralportions of wafers W. When the loading/unloading hand 220 is raised, theloading/unloading hand 220 enters a wafer carrier C mounted on the stage216 through an opening formed in the bottom wall of the wafer carrier Cand lifts up a plurality of wafers W contained in the wafer carrier C.

[0102] A pitch changer 221 is mounted on the stage 216. The pitchchanger 221 is capable of rearranging the plurality of wafers W(twenty-six wafers) lifted up from the wafer carrier C by theloading/unloading hand 220 at a pitch equal to half a pitch at which thewafers W are arranged in the wafer carrier C to arrange the wafers W ina length equal to about half the length in which the wafers W arearranged in the wafer carrier C.

[0103] As shown in FIG. 22, the wafer carrying device 208 hasstretchable wafer support arms 224 a and 224 b capable of being movedtoward and away from each other and a slide base 225 capable of slidingalong a guide rail 226 in the directions of the arrows X.

[0104] The wafer carrier storage unit 204 has wafer carrier keepingdevices 227 and 228 and a wafer carrier cleaner 229, which are arrangedin a row. The wafer carrier keeping devices 227 and 228 are used fortemporarily keeping empty wafer carriers C emptied by taking out notcleaned wafers W therefrom in the loading/unloading unit 203 and forkeeping clean wafer carriers C for containing cleaned wafers W. Thewafer carrier carrying table 207 carries a wafer carrier C into a vacantspace in the storage device 227 or 228 and carries out a wafer carrier Cfrom the storage device 227 or 228.

[0105] The wafer carrier carrying table 207 may carry a wafer carrier Cinto and may take out a wafer carrier C from a specified place in eitherthe storage device 227 or 228. When the wafer carrier carrying table 207is operated in such a mode, the storage unit 204 is provided with alifter, not shown, a the lifter transfers a wafer carrier C from thespecified place to a vacant place in the storage device 227 or 228 andtransfers a stored wafer carrier C from a storage place in the storagedevice 227 or 228 to the specified place.

[0106] The cleaning unit 206 will be described with reference to FIGS.24 to 38. A cleaning device 20 provided at the cleaning unit 206 isidentical with the cleaning device 20 employed in the first embodimentand hence the description thereof will be omitted to avoid duplication.

[0107] In the cleaning unit 206, a wafer hand 233 or a wafer lifter isdisposed below the rotor 24 of the cleaning device 20. The wafer hand233 can be vertically moved between a wafer transfer position 234 inwhich wafers W are put on and taken off the wafer hand 233 and a waitingposition 235 where the wafer hand 233 is kept for waiting. The waitingposition 235, the rotor 24 and the transfer position 234 are arranged inthat order.

[0108] Referring to FIGS. 24 to 26, the wafer hand 233 i.e., thesubstrate moving mechanism is equipped with a first support plate 300(i.e., a substrate support member) for supporting wafers W from belowthe same, a second support plate 301 (i.e., a substrate support member)for supporting wafers W from below the same, a lifting mechanism 302mounted on the second support plate 301, and a base 303 on which thesecond support plate 301 is mounted.

[0109] First support members 304 and 305 are fixed to laterally oppositeends of the first support plate 301, respectively. A plurality ofgrooves 309 for receiving lower peripheral portions of wafers W arearranged at a predetermined pitch in the upper end surfaces of the firstsupport members 304 and 305 extending perpendicularly to the paper.

[0110] A lifting rod 307 included in the lifting mechanism 302 isconnected to the lower surface of the first support plate 300. Secondsupport members 308 and 309 are fixed to the upper surface of the secondsupport plate 301 so as to project into a space between the firstsupport members 304 and 305. The second support members 308 and 309extend through and project upward from the first support plate 300. Aplurality of grooves 310 for receiving lower peripheral portions ofwafers W are arranged at a predetermined pitch in the upper end surfacesof the second support members 308 and 309 extending perpendicularly tothe paper.

[0111] When the lifting rod 307 of the lifting mechanism 302 is extendedto raise the first support plate 300 so that the upper ends of the firstsupport members 304 and 305 are on a level above that of the upper endsof the second support members 308 and 309, lower peripheral portions ofwafers W can be supported on only the first support members 304 and 305.

[0112] When the lifting rod 307 of the lifting mechanism 302 isretracted to lower the first support plate 300 so that the upper ends ofthe first support members 304 and 305 are on a level lower than that ofthe upper ends of the second support members 308 and 309, lowerperipheral portions of wafers W can be supported on only the secondsupport members 308 and 309 as shown in FIG. 27. Therefore, when thefirst support members 304 and 305 are used for supporting not cleanedwafers W and the second support members 308 and 309 are used forsupporting cleaned wafers W, it is possible to prevent contamination ofthe cleaned wafers W with particles fallen off the not cleaned wafers Wand adhering to the first support members 304 and 305.

[0113] The base 303 of the wafer hand 233 is put on and connected to theupper end of a support rod 320. The support rod 320 is fixedly supportedon a lifting member 322 that is moved vertically along a guide rail 321,i.e., in the directions of the arrows Z in FIGS. 24 and 25. In FIG. 24,the wafer hand 233 indicated by continuous lines is at a lower waitingposition in the waiting position 235, and the wafer hand 233 indicatedby two-dot chain lines (233′) is in the transfer position 234 to receivewafers W from the wafer carrying device 208 or to transfer wafers W tothe wafer carrying device 208.

[0114] The base 303 has a horizontal top part 311 to which the secondsupport plate 301 is fixed, a vertical side part 312 supporting the toppart 311 in a horizontal position and a horizontal bottom part 313supporting the side part 312 in a vertical position. A space 314 isformed between the top part 312 and the bottom part 313. The wafersupport arms 224 a and 224 b of the wafer carrying device 208 areextended through the space 314.

[0115] A series of operations of the wafer cleaning apparatus will bedescribed. Two wafer carriers C each containing, for example, twenty-sixwafers W to be cleaned are carried to the in/out port 202 and are placedat the stations 212 and 213 by, for example, an operator. The wafercarrier carrying table 207 carries the wafer carrier C placed at thestation 2-13 to the loading/unloading unit 203. In the loading/unloadingunit 302, the wafers W are unloaded from the wafer carrier C, and thetwenty-six wafers W are rearranged at a pitch equal to about half apitch at which the wafers W are arranged in the wafer carrier C by thepitch changer 221 in a wafer group. Subsequently, the wafer carrier Cplaced at the station 212 is carried to the loading/unloading unit 203,the twenty-six wafers W are unloaded from the wafer carriers C and thewafers W are rearranged at a pitch equal to about half a pitch at whichthe wafers W are arranged in the wafer carrier C in a wafer group. Thewafer groups each of the twenty-six wafers W are combined to form awafer group of the fifty-two wafers W arranged at a pitch equal to abouthalf a pitch at which the wafers W are arranged in the wafer carriers W.

[0116] The wafer carrying device 208 holds the wafer group of thefifty-two wafers and carries the same to the cleaning unit 206. Thewafer carrying device 208 moves to the transfer position 234, i.e, awafer waiting portion in the cleaning unit 206 as shown in FIG. 28.

[0117] The outer covering wall 26 and the inner covering wall 27 of thecleaning device are retracted to their back positions.

[0118] Then, as shown in FIG. 29, the wafer hand 233 is raised towardthe transfer position 234. The wafer lifting hand 233 with itscomponents set in an arrangement shown in FIG. 26 is raised throughspaces between the corresponding holding members of the rotor 24.

[0119] As shown in FIG. 30, the wafer hand 233 raised into the transferposition 234 lifts up the not cleaned wafers W from the wafer supportarms 224 a and 224 b to receive the wafers W from the wafer carryingdevice 208. When the wafers W are thus transferred from the wafercarrying device 208 to the wafer hand 233, the wafer support arms 224 aand 224 b are on the level of the space 314 as shown in FIG. 24.Therefore, the wafer support arms 224 a and 224 b can be moved throughthe space 314 to retract the wafer carrying device 208 from the wafercleaning device 205 (FIG. 31).

[0120] Since the wafer holding arms 224 a and 224 b of the wafercarrying device 208 are moved only laterally and the wafer band 233supports the wafer W from below the same, the transfer operation fortransferring the wafers W from the wafer carrying device 208 to thewafer hand 233 is not obstructed and can be easily achieved. Therefore,the wafer carrying device 208 can be controlled by a control program ofa simple algorithm, the wafer holding arms 224 a and 224 b do not needto be provided with any obstacle sensor and any complicated feedbackcontrol apparatus for controlling the wafer carrying device 208 is notnecessary.

[0121] After the wafer carrying device 208 has been moved away from thecleaning unit 206 as shown in FIG. 32, the wafer hand 233 is lowered asshown in FIG. 33. As the wafer hand 233 is lowered toward the waitingposition 235, the wafers W are transferred from the wafer hand 233 tothe first holding members 71 a and 72 b and the second holding members72 a and 72 b of the rotor 24 as shown in FIG. 34. The wafer hand 233 isstopped temporarily or the lowering speed of the wafer hand 233 isreduced immediately before the wafers W come into contact with theholding members 71 a, 71 b, 72 a and 72 b for safety.

[0122] Then, the holding mechanisms 73 a and 73 b of the rotor 24 isoperated to bring third holding members 288 a and 288 b into engagementwith peripheral portions of the wafers W so that the wafers W are heldsecurely on the rotor 24.

[0123] The outer covering wall 26, the inner covering wall 27, the rotor24 and other components of the cleaning unit 206 are operated by thesame procedure as that previously described in connection with the firstembodiment to carry out the cleaning process and the drying process.During the cleaning process and the drying process, the wafer hand 233is held in the waiting position.

[0124] After the completion of the cleaning process and the dryingprocess, the outer covering wall 26 and the inner covering wall 27 areretracted to their back positions and the wafers W are carried out ofthe wafer cleaning device 205.

[0125] The components of the wafer lifting hand 233 are set in anarrangement as shown in FIG. 27 and the steps previously described withreference to FIGS. 28 to 35 are revised. Thus, the cleaned wafers W areheld by the wafer carrying device 208. During those operations forholding the cleaned wafers W by the wafer carrying device 208, the wafersupport arms 224 a and 224 b of the wafer carrying device 208 are moveonly laterally. The wafer carrying device 208 carries the cleaned wafersW to the loading/unloading unit 203. Then, the cleaned wafers W are putin wafer carriers C and the wafer carriers C are placed at the stations214 and 215 of the in/out port 202. Then, the wafer carriers Ccontaining the cleaned wafers W are delivered to the next destination.

[0126] Various modifications are possible in the cleaning apparatus inthe second embodiment. For example, wafers W may be transferred from thewafer carrying device 208 to the wafer hand 233 at a position below therotor 24 as shown in FIG. 36. In this case, the wafer carrying device208 holding the wafers W is located at a position above the wafer hand233 and below the rotor 24 (i.e., wafer waiting portion), and then thewafers W are transferred from the wafer carrying device 208 to the waferhand 233 by a procedure similar to that described previously withreference to FIGS. 29 to 31. The procedure is different from thatdescribed in connection with FIGS. 29 to 31 only in the position wherethe wafers W are transferred from the wafer carrying device 208 to thewafer hand 233. The wafers W are transferred from the wafer hand 233 tothe rotor 24 by the same procedure as that described previously inconnection with the first embodiment with reference to FIGS. 16 to 18,in which the wafer hand 233 is used instead of the wafer supportingmember 41.

[0127] A wafer hand 340 shown in FIG. 37 may be employed instead of thewafer hand 233. The wafer holding device 340 has a base 303 and asupport member 341 slidable on the base 303. The support member 341 isprovided in its upper surface with wafer holding grooves 342. The numberof the grooves 342 is twice (or an integral multiple greater than twiceof) the number of the grooves 306 (309) formed in the first supportmembers 304 and 305 (the second support members 307 and 308). The pitchof the grooves 342 is half that of the grooves 306 (309). Therefore, thecleaned wafers W can be received in the grooves different from those inwhich the not cleaned wafers W had been received before the same werecleaned by longitudinally shifting the support member 341 by a distanceequal to the pitch of the grooves 342, so that contamination of thecleaned wafers w with particles and such adhering to the grooves inwhich the not cleaned wafers W had been received before the same werecleaned can be prevented. A wafer carrying device 350 shown in FIG. 38may be employed instead of the wafer carrying device 208. The wafercarrying device 350 has wafer support members 351 a and 351 b providedin their inner surfaces with wafer holding grooves 352. The number ofthe grooves 352 is twice (or an integral multiple greater than twice of)the number of the grooves formed in the wafer support arms 224 a and 224b of the wafer carrying device 208. The pitch of the grooves 352 is halfthat of the grooves of the wafer support arms 224 a and 224 b.Therefore, the cleaned wafers W can be received in the grooves differentfrom those in which the not cleaned wafers W had been received beforethe same were cleaned by longitudinally shifting the wafer support arms351 a and 351 b by a distance equal to the pitch of the grooves 352, sothat contamination of the cleaned wafers W with particles and suchadhering to the grooves in which the not cleaned wafers W had beenreceived before the same were cleaned can be prevented.

[0128] Although the invention has been described in its preferredembodiments as applied to the cleaning apparatus, the present inventionis not limited thereto in its practical application. The presentinvention is applicable to liquid application apparatus for applying apredetermined coating liquid to workpieces, CVD apparatus, etchingapparatus and the like. The substrates are not limited to semiconductorwafers, but may be LCD plates and such.

What is claimed is:
 1. A substrate processing apparatus comprising: asubstrate processing portion at which a plurality of substrates aretreated by a process; a substrate waiting portion at which thesubstrates stand by for the process, the waiting portion being arrangedbelow the processing portion; and a substrate lifter including asubstrate supporting member configured to support the substrates frombelow the substrates, the supporting member being capable of verticalmovement, wherein the lifter supports the substrates placed at thewaiting portion and raises the substrates thereby moves the substratesfrom the waiting portion to the processing portion, and wherein thelifter supports the substrates placed in the processing portion andlowers the substrates thereby moves the substrates from the processingportion to the waiting portion.
 2. The substrate processing apparatusaccording to claim 1 further comprising a substrate container carrierconfigured to carry a substrate container to the waiting portion andcarrying out a substrate container from the waiting portion; wherein thesubstrates are contained in the container while the substrates arestanding by in the waiting portion.
 3. The substrate processingapparatus according to claim 1, wherein the substrate processing portionis provided with a substrate holding device configured to hold thesubstrates while the substrates are being treated and a covering memberdefining at least part of a processing chamber in which the substrateholding device is disposed, and wherein the substrate waiting portionand the substrate lifter are disposed below the substrate holding deviceand substrates are transferred between the substrate holding device andthe substrate supporting member.
 4. The substrate processing apparatusaccording to claim 3 further comprising a substrate container carrierconfigured to carry the container into the substrate waiting portion andto carry the container from the substrate waiting portion, wherein thesubstrates are contained in the container while the substrates arestanding by at the waiting portion.
 5. The substrate processingapparatus according to claim 3 further comprising a shock absorberpreventing application of an excessive load to the substrates when thesubstrates are raised and brought into contact with the substrateholding device by the substrate lifter.
 6. The substrate processingapparatus according to claim 5, wherein the shock absorber comprises: acylinder actuator supporting the substrate supporting member of thesubstrate lifter, the cylinder actuator having a relief mechanism; aload sensor measuring a load applied to the substrates; and a controllerthat actuates the relief mechanism to discharge a working medium foroperating the cylinder actuator from the cylinder actuator when the loadmeasured by the load sensor exceeds a threshold.
 7. The substrateprocessing apparatus according to claim 3, wherein the covering memberis capable of moving between a first position to define the processingchamber surrounding the substrate holding device and a second positionapart from the substrate holding device to expose the substrate holdingdevice.
 8. The substrate processing apparatus according to claim 3further comprising a liquid supplying portion configured to supply aprocessing liquid into the processing chamber.
 9. The substrateprocessing apparatus according to claim 8, wherein the covering memberis capable of moving between a first position to define the processingchamber surrounding the substrate holding device and a second positionapart from the substrate holding device to expose the substrate holdingdevice; and the covering member is provided with a drip preventingdevice configured to prevent dripping of the processing liquid when thecovering: member is moved from the first position to the secondposition.
 10. The substrate processing apparatus according to claim 9further comprising a wall with which the covering member is engaged todefine at least part of the processing chamber; wherein the drippreventing device includes a processing liquid receiving elementconfigured to receive the processing liquid, and a pressing elementconfigured to press the processing liquid receiving member against thewall when the covering member is placed at the first position.
 11. Thesubstrate processing apparatus according to claim 3, wherein thesubstrate processing portion is further provided with a second coveringmember defining at least part of a second processing chamber in thefirst processing chamber defined by the first covering member, thesecond covering member being capable of moving between a first positionto surround the substrate holding device in the first processing chamberand a second position outside the first processing chamber.
 12. Thesubstrate processing apparatus according to claim 3, wherein thesubstrate holding-device is a rotor.
 13. The substrate processingapparatus according to claim 3, wherein the substrate holding deviceincludes: a body; a first holding element fixedly attached to the body;and a second holding elements movably attached to the body; and whereinthe second holding elements is capable of moving between a firstposition to hold the substrates at a substrate holding area in thesubstrate holding device in cooperation with the first holding element,and a second position to allow the substrates to be carried into and outof the substrate holding area.
 14. The substrate processing apparatusaccording to claim 3, wherein the substrate waiting portion is providedwith a stage on which a substrate container is placed, and the stage isprovided with an opening through which the substrate supporting membercan vertically move.
 15. The substrate processing apparatus according toclaim 14, wherein the stage is capable of moving into and out of thesubstrate waiting portion.
 16. The substrate processing apparatusaccording to claim 3, wherein the substrate supporting member isprovided with first grooves for holding substrates before being treatedand second grooves for holding substrates after being treated, the firstand second grooves being arranged alternately.
 17. A substrateprocessing apparatus comprising: a substrate processing portion at whicha plurality of substrates are treated by a process; a substrate waitingportion at which the substrates stand by for the process, the waitingportion being arranged above the processing portion; and a substratelifter including a substrate supporting member configured to support thesubstrates from below the substrates, the supporting member beingcapable of vertical movement, wherein the lifter supports the substratesplaced at the waiting portion and lowers the substrates thereby movesthe substrates from the waiting portion to the processing portion, andwherein the lifter supports the substrates placed in the processingportion and raises the substrates thereby moves the substrates from theprocessing portion to the waiting portion, and wherein the lifter isdisposed outside of the processing portion.
 18. The substrate processingapparatus according to claim 17 wherein the substrate processing portionis provided with a substrate holding device configured to hold thesubstrates while the substrates are being treated and a covering memberdefining at least part of a processing chamber in which the substrateholding device is disposed, and wherein the covering member is capableof moving between a first position to define the processing chambersurrounding the substrate holding device and a second position apartfrom the substrate holding device to expose the substrate holdingdevice.
 19. A substrate processing method comprising the steps of:carrying a substrate container containing a plurality of substrates intoa container waiting portion disposed below a substrate processingportion for processing substrates; supporting the substrates containedin the substrate container, and raising the substrate to the processingportion disposed above the waiting portion; treating the substrates by aprocess at the substrate processing portion; supporting the substrateswhich have been treated and lowering the substrates into a substratecontainer; and carrying out the substrate container containing theprocessed substrates, which have been treated, from the waiting portion.20. The substrate processing method according to claim 19, wherein thesubstrates are supported on a first area of the substrate supportingmember when the substrates are raising from the waiting portion to theprocessing portion before being treated, and the substrates aresupported on a second area of the substrate supporting member when thesubstrates are lowering from the processing portion to the waitingportion after being processed, the second area being different from thefirst area.
 21. A substrate processing method comprising the steps of:holding a plurality of substrates by an arm and carrying a substratesinto a substrate waiting portion disposed above a substrate processingportion; delivering the substrates from the arm to a supporting member;lowering the supporting member thereby moving the substrates to theprocessing portion; holding the substrates by a substrate holding deviceprovided at the processing portion; further lowering the supportingmember thereby withdrawing the supporting member from the processingportion; and treating the substrates by a process at the substrateprocessing portion.